Founded in January 2000 by Panasonic, SanDisk and Toshiba, the SD Association is a group dedicated to establishing SD standards and facilitating their adoption and development.
At its outset the Association represented just 14 member companies and has grown into a global alliance comprised of around 1,000 member companies. By developing and adopting SD standards, members enjoy better compatibility of member cards between devices, greatly enhancing consumer enjoyment and convenience.

Maximum speed differs from the bus I/F speed. It varies depending upon the card performance. The average speed that a device writes to an SD memory card may vary depending upon the device and the operation it is performing. The speed may also depend on how other data is stored on the SD memory card.

Normal and high-speed cards can also be used with UHS-I host devices, but the high performance enabled by a UHS-I host device can only be achieved with a UHS-I memory card.

UHS-II Pin Layout

A new pin layout was introduced to support the UHS-II bus interface. The new second-row pins on the full-size SD memory card and microSD memory card are used for the UHS-II signals. The first-row pins are used for the normal speed, high speed and UHS-I bus interface signals to provide interoperability with existing non-UHS-II host devices.

Normal Speed/High Speed/UHS-I Card

UHS-II Card

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